Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
1998-07-27
2001-09-18
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S051000, C475S149000, C477S205000, C074S733100
Reexamination Certificate
active
06292731
ABSTRACT:
TECHNICAL FIELD
The invention comprises an automatic transmission control system capable of providing an automatic ratio changing mode and manual ratio selection modes.
BACKGROUND OF THE INVENTION
The invention comprises improvements in an automatic transmission control system of the kind shown in U.S. Pat. Nos. 5,612,874; 5,586,029; and 5,642,283. Each of these prior art patents is assigned to the assignee of the present invention. Their disclosures are incorporated in this disclosure by reference.
The present invention includes features that are common to each of the prior art patents identified above. The '874 patent describes an automatic upshift and downshift control for a four-speed ratio version of the transmission gearing of the present invention. The control includes a pressure build-up system with one variable force solenoid. The electronic control pressure that responds to control strategy executed by an electronic microprocessor is distributed to a booster valve in the main regulator valve system. The main regulator valve effects control of the brake capacity and clutch capacity for all operating conditions. The regulator valve system can be calibrated to provide appropriate pressure needed for achieving the smooth ratio changes without affecting the control strategy required to maintain clutch and brake capacity under stall conditions. Conventional accumulators are not required to soften the engagement of the clutch and the brakes since the pressure boost system is capable of adjusting the capacity of the main regulator valve to achieve optimum upshift and downshift smoothness. A separate valve system is used for forward drive engagements and for reverse drive engagements.
The '029 patent describes a transmission having a compound multiple ratio gear set in combination with a simple planetary gear set as in the case of the present invention. A first overrunning coupling establishes a reaction element for the simple planetary gear set and a second overrunning coupling in the multiple ratio gear set is used for the purpose of establishing non-synchronous shifts in the multiple ratio gear set. In each instance, a forward engagement is obtained by engaging a forward clutch. A separate reverse engagement clutch is used to establish a torque flow path for reverse. In each instance, turbine speed is used as a feedback signal to initiate the start of either the forward engagement or the reverse engagement.
The '283 patent, like the '874 and the '029 patents, has a three-speed ratio gear set in series with a simple planetary gear set. It provides five forward driving ratios, however, rather than four. So-called “swap-shifts” are achieved as the multiple ratio gear set is upshifted and the simple planetary gear set is downshifted. Conversely, an upshift of the simple planetary gear set occurs as the multiple ratio gear set is downshifted. The torque reaction point for the overall transmission gearing is transferred from the multiple ratio gear set to the simple planetary gear set on a downshift and is transferred from the simple planetary gear set to the multiple ratio gear set on an upshift.
BRIEF DESCRIPTION OF THE INVENTION
The control system of the present invention is capable of being used with five-speed gearing as well as four-speed gearing such as that described in the '874, '029 and '283 patents. It is capable of being used also with a five-speed transmission gear system that employs synchronous 3-4 upshifts and 4-3 downshifts using the swap-shift technique described in the preceding discussion and with a transmission having a mechanically synchronized 3-4 upshift and a 4-3 downshift using an overrunning coupling on the reaction elements to achieve non-synchronous ratio changes. A control system having common elements may be used for both transmission versions. The valve system can be designed with reduced complexity because of the common functions of the valve elements.
Each of the control systems is capable of providing a so-called “select-shift” manual control mode as well as a manual control mode and a fully automatic control mode. The synchronous swap-shifts between the second and the third ratio and between the third ratio and the second ratio and the non-synchronous upshifts and downshifts between the first and second ratios and between the fourth and the fifth ratios are common for each of these control modes. Engine braking may be provided in each gear in the select-shift manual control mode as well as in the manual control mode. Free-wheeling is available when the transmission is in the so-called automatic control mode.
All of these functions can be achieved by the control system of the present invention using only three variable force solenoids. The variable force solenoids are multiplexed in cooperation with pressure modulator valves for the clutches and brakes. For purposes of this disclosure, the verb “multiplexed” is used in describing variable force solenoids that have multiple functions depending upon the operating mode that is selected by the vehicle operator, thereby eliminating the need for providing a separate variable force solenoid for each function.
The invention includes further an improved main regulator valve system using two variable force solenoids with a main regulator valve, which ensures a sufficiently high feed pressure to protect the forward clutch capacity. Separate on/off solenoids are used to control the operation of shift valves, which in turn distribute control pressure to the transmission clutches and brakes. A separate on/off solenoid is used to control the braking of the reaction element in the simple planetary gear unit and in the multiple ratio gear unit.
REFERENCES:
patent: 4817473 (1989-04-01), Baltusis et al.
patent: 5553694 (1996-09-01), Schulz et al.
patent: 5586029 (1996-12-01), Schulz et al.
patent: 5612874 (1997-03-01), Schulz et al.
patent: 5642283 (1997-06-01), Schulz et al.
patent: 5646842 (1997-07-01), Schulz et al.
patent: 5722519 (1998-03-01), Kirchhoffer et al.
patent: 5758302 (1998-05-01), Schulz et al.
patent: 6007445 (1999-12-01), Kirchhoffer et al.
“Porsch Tiptronic”, Von Ulrich Maier et al, Automobiltechnische Zeltschrift 92, 1990, pp. 308-319, including German-to-English translation.
Crandall Scott Raymond
Croonen Werner
Haase Robert Cary
Kirchhoffer Johann
Reichert Eric
Cuchlinski Jr. William A.
Ford Global Technologies Inc.
McKenzie Frank G.
To Tuan C
LandOfFree
Automatic shift control system for an automatic transmission... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Automatic shift control system for an automatic transmission..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic shift control system for an automatic transmission... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2532880